Method and system for removal of oxygen in oxidative dehydrogenation process

ABSTRACT

The present invention relates generally to methods and systems for removing oxygen from at least one product stream of a hydrocarbon oxidative dehydrogenation process. More specifically, in some embodiments, the oxidative dehydrogenation process is an ethane oxidative dehydrogenation process for producing ethylene, or a mixed alkane oxidative dehydrogenation process for producing ethylene and propylene, among other components.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation-in-part (“CIP”) of Non-provisionalapplication Ser. No. 15/921,310, filed Mar. 14, 2018, entitled “METHODAND SYSTEM FOR REMOVAL OF OXYGEN IN OXIDATIVE DEHYDROGENATION PROCESS”,the entire contents of which are herein incorporated by reference.

FIELD OF THE INVENTION

The present invention relates generally to methods and systems forremoving oxygen from at least one product stream of a hydrocarbonoxidative dehydrogenation process. More specifically, in someembodiments, the oxidative dehydrogenation process is an ethaneoxidative dehydrogenation process for producing ethylene. In otherembodiments, the oxidative dehydrogenation process is a mixed alkaneoxidative dehydrogenation process.

BACKGROUND

All publications herein are incorporated by reference to the same extentas if each individual publication or patent application was specificallyand individually indicated to be incorporated by reference. Thefollowing description includes information that may be useful inunderstanding the present invention. It is not an admission that any ofthe information provided herein is prior art or relevant to thepresently claimed invention, or that any publication specifically orimplicitly referenced is prior art.

Ethylene is a commercial and industrially important petrochemical usedfor the manufacture of polymers and various chemical products. Oneprocess for producing ethylene is the catalytic dehydrogenation ofethane in the presence of oxygen. This process is called oxidativedehydrogenation (ODH). In the oxidative dehydrogenation of ethane, themajor component in the product is ethylene, however smaller amounts ofimpurities such as oxygen, carbon dioxide, and carbon monoxide are alsopresent in the oxidative dehydrogenation product. In other embodiments,the oxidative dehydrogenation process is a mixed alkane oxidativedehydrogenation process. It is important to reduce and/or remove theamount of oxygen in the oxidative dehydrogenation product, since theoxygen can cause a number of problems during the handling of theoxidative dehydrogenation product, and/or during the recovery of theethylene therefrom. As such there is a need in the art for methods andsystems for reducing and/or removing the amount of oxygen from anoxidative dehydrogenation product and/or a product stream of anoxidative dehydrogenation process. In various embodiments, the methodsand systems of the present invention meet that need.

SUMMARY OF THE INVENTION

The following embodiments and aspects thereof are described andillustrated in conjunction with systems, articles of manufacture,compositions and methods which are meant to be exemplary andillustrative, not limiting in scope.

In various embodiments, the present invention provides a method forremoving oxygen from a product stream of an oxidative dehydrogenationprocess, comprising: contacting the product stream of the oxidativedehydrogenation process with at least one oxygen removal catalyst in atleast one oxygen removal reactor, wherein the product stream has abaseline oxygen content; recovering a first effluent stream from the atleast one oxygen removal reactor, wherein the first effluent stream hasa first oxygen content, wherein the first oxygen content of the firsteffluent stream is reduced compared to the baseline oxygen content ofthe product stream; contacting the first effluent stream with at leastone oxygen absorbent in at least one absorber unit; and recovering asecond effluent stream from the at least one absorber unit, wherein thesecond effluent stream has a second oxygen content, wherein the secondoxygen content of the second effluent stream is reduced compared to thefirst oxygen content of the first effluent stream. In some embodiments,the method further comprises heating the product stream beforecontacting the product stream with the at least one oxygen removalcatalyst. In some embodiments, the heating is effected at a temperatureof 100° C. to 600° C. In some embodiments, the method further comprisescooling the first effluent stream before contacting the first effluentstream with the at least one oxygen absorbent. In some embodiments, thecooling is effected at a temperature of 25° C. to 130° C. In someembodiments, the at least one oxygen removal catalyst comprises at leastone metal selected from Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt, and Mn. Insome embodiments, the at least one metal is Pd. In other embodiments,the at least one metal is Mn. In some embodiments, the at least oneoxygen absorbent comprises at least one metal selected from Cu, Ag, Au,Zn, Cd, and Hg. In some embodiments, the at least one metal is Cu. Insome embodiments, the at least one oxygen absorbent comprises amolecular sieve. In some embodiments, the molecular sieve is selectedfrom a type 3A, a type 4A, and any combination thereof. In someembodiments, the product stream comprises at least one alkane, at leastone alkene, oxygen, and carbon monoxide. In some embodiments, the atleast one alkene is selected from C₂-C₅ alkenes. In some embodiments,the at least one alkene is ethylene. In some embodiments, the productstream comprises at least two alkanes, at least two alkenes, carbonmonoxide, carbon dioxide, water and oxygen. In some embodiments the atleast two alkanes comprise three alkanes. In some embodiments, the atleast two alkenes are ethylene and propylene. In some embodiments, theproduct stream comprises ethylene and propylene, methane, ethane,propane, carbon monoxide, carbon dioxide, water and oxygen. In someembodiments where the product stream from the oxidative dehydrogenationprocess comprises water, it is not necessary to remove the water fromthe product stream before introducing the water-containing productstream into the oxygen removal reactor inlet. In the embodimentsdescribed herein, unreacted (free) hydrogen is not present in theproduct stream, nor is it introduced into the oxygen removal reactorinlet. Nor are other hydrocarbons introduced into the product stream oroxygen removal reactor inlet. The only hydrocarbons present (other thanminor impurities formed during the oxidative dehydrogenation process)are those described herein as the components of the product stream.Other hydrocarbons present as minor impurities, if present, are presenton the order of several parts per billion by volume (“ppbv”). In someembodiments, the oxygen content of the first effluent stream aftercontacting the product stream with the Mn-based catalyst effects morethan 72.5% reduction as compared with the baseline content of theproduct stream. In some embodiments, the oxygen content of the firsteffluent stream after contacting the product stream with the Mn-basedcatalyst effects more than 90% reduction as compared with the baselinecontent of the product stream. In some embodiments, the second oxygencontent of the second effluent stream is less than or equal to 500 partsper million by volume (ppmv). In some embodiments, a ratio of the secondoxygen content of the second effluent stream relative to the firstoxygen content of the first effluent stream is less than 15%. In someembodiments, the product stream has a baseline gas hourly space velocity(GHSV) of 100 to 12,000 hr⁻¹ in the at least one oxygen removal reactor.In some embodiments, the first effluent stream has a first gas hourlyspace velocity (GHSV) of 100 to 12,000 hr⁻¹ in the at least one absorberunit. In some embodiments, the heating is effected by a heater or acombination of the heater and a heat recover exchanger. In someembodiments, the cooling is effected by a cooler. In some embodiments,the at least one oxygen removal catalyst is in the form of a catalystbed. In some embodiments, the at least one oxygen absorbent is in theform of an absorbent bed.

In various embodiments, the present invention provides an oxygen removalsystem for removing oxygen from a product stream of an oxidativedehydrogenation process, comprising: at least one oxygen removal reactorfor preparing a first effluent stream, wherein the at least one oxygenremoval reactor comprises at least one oxygen removal catalyst, an inletfor the product stream, and an outlet for the first effluent stream; asupply line for transporting the product stream of the oxidativedehydrogenation process to the at least one oxygen removal reactor,wherein the product stream has a baseline oxygen content; a heater forheating the product stream; a cooler for cooling the first effluentstream; and at least one absorber unit for preparing a second effluentstream, wherein the at least one absorber unit comprises at least oneoxygen absorbent, an inlet for the first effluent stream, and an outletfor the second effluent stream; wherein the heater is connected to thesupply line for transporting the product stream to the at least oneoxygen removal reactor; wherein the at least one oxygen removal reactoris connected to the heater; wherein the cooler is connected to the atleast one oxygen removal reactor; and wherein the at least one absorberunit is connected to the cooler.

In some embodiments, the oxygen removal system further comprises, a heatrecovery exchanger for optionally heating the product stream, whereinthe heat recovery exchanger is: (i) connected to the supply line fortransporting the product stream of the oxidative dehydrogenation processto the at least one oxygen removal reactor; (ii) connected to theheater; (iii) connected to the at least one oxygen removal reactor; and(iv) connected to the cooler; wherein, the at least one oxygen removalreactor is connected to the heater; and wherein, the at least oneabsorber unit is connected to the cooler. In some embodiments, the heatrecovery exchanger is for optionally heating the product stream byutilizing recoverable heat from the first effluent stream. In someembodiments, the at least one oxygen removal catalyst comprises at leastone metal selected from Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt, and Mn. Insome embodiments, the at least one oxygen absorbent comprises at leastone metal selected from Cu, Ag, Au, Zn, Cd, and Hg. In some embodiments,the at least one oxygen absorbent comprises a molecular sieve. In someembodiments, the product stream comprises at least one alkane, at leastone alkene, oxygen, and carbon monoxide. In some embodiments, theproduct stream has a baseline gas hourly space velocity (GHSV) of 100 to12,000 hr⁻¹ in the at least one oxygen removal reactor. In someembodiments, the at least one oxygen removal catalyst is an Mn-basedoxygen removal catalyst. In some embodiments the Mn-based oxygen removalcatalyst has the formula MnOx. In some embodiments, the Mn-based oxygenremoval catalyst is a mixed oxide of Mn and at least one other metal. Insome embodiments, the at least one other metal in the Mn-based oxygenremoval catalyst is at least one selected from the group consisting ofCu, Ce, and Al. In some embodiments the mixed oxide of Mn comprisesMnOx, and at least one metal oxide from the group consisting of CuO,CeO₂ and Al₂O₃. In some embodiments, the at least one oxygen removalcatalyst is in the form of a catalyst bed. In some embodiments, the atleast one oxygen absorbent is in the form of an absorbent bed. In someembodiments, the heater is effected at a temperature of 100° C. to 600°C., preferably in the range of 150° C. to 250°. In some embodiments, thecooler is effected at a temperature of 25° C. to 130° C., preferably inthe range of 40° C. to 50° C. In some embodiments, the at least oxygenremoval catalyst comprises at least one metal selected from Pd. In someembodiments, the at least one oxygen absorbent comprises at least onemetal selected from Cu. In some embodiments, the molecular sieve isselected from a type 3A, a type 4A, and any combination thereof. In someembodiments, the at least one alkene is selected from C₂-C₅ alkenes. Insome embodiments, the at least one alkene is ethylene. In someembodiments, the first effluent stream has a first oxygen content. Insome embodiments, the first oxygen content of the first effluent streamis reduced compared to the baseline oxygen content of the productstream. In some embodiments, the second effluent stream has a secondoxygen content. In some embodiments, the second oxygen content of thesecond effluent stream is reduced compared to the first oxygen contentof the first effluent stream. In some embodiments, the second oxygencontent of the second effluent stream is less than or equal to 500 partsper million by volume (ppmv). In some embodiments, the first effluentstream has a first gas hourly space velocity (GHSV) of 100 to 12,000hr⁻¹ in the at least one absorber unit.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments are illustrated in referenced figures. It isintended that the embodiments and figures disclosed herein are to beconsidered illustrative rather than restrictive.

FIG. 1 depicts in accordance with various embodiments of the invention,a schematic diagram showing an embodiment of the present invention.

FIG. 2 depicts in accordance with various embodiments of the invention,a schematic diagram showing an embodiment of the present invention.

FIG. 3 depicts, in accordance with another embodiment of the invention,a schematic diagram showing an embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

All references cited herein are incorporated by reference in theirentirety as though fully set forth. Unless defined otherwise, technicaland scientific terms used herein have the same meaning as commonlyunderstood by one of ordinary skill in the art to which this inventionbelongs.

One skilled in the art will recognize many methods and materials similaror equivalent to those described herein, which could be used in thepractice of the present invention. Other features and advantages of theinvention will become apparent from the following detailed description,taken in conjunction with the accompanying drawings, which illustrate,by way of example, various features of embodiments of the invention.Indeed, the present invention is in no way limited to the methods andmaterials described. For convenience, certain terms employed herein, inthe specification, examples and appended claims are collected here.

Unless stated otherwise, or implicit from context, the following termsand phrases include the meanings provided below. Unless explicitlystated otherwise, or apparent from context, the terms and phrases belowdo not exclude the meaning that the term or phrase has acquired in theart to which it pertains. Unless otherwise defined, all technical andscientific terms used herein have the same meaning as commonlyunderstood by one of ordinary skill in the art to which this inventionbelongs. It should be understood that this invention is not limited tothe particular methodology, protocols, and reagents, etc., describedherein and as such can vary. The definitions and terminology used hereinare provided to aid in describing particular embodiments, and are notintended to limit the claimed invention, because the scope of theinvention is limited only by the claims.

As used herein the term “comprising” or “comprises” is used in referenceto compositions, methods, systems, articles of manufacture, andrespective component(s) thereof, that are useful to an embodiment, yetopen to the inclusion of unspecified elements, whether useful or not. Itwill be understood by those within the art that, in general, terms usedherein are generally intended as “open” terms (e.g., the term“including” should be interpreted as “including but not limited to,” theterm “having” should be interpreted as “having at least,” the term“includes” should be interpreted as “includes but is not limited to,”etc.). Although the open-ended term “comprising,” as a synonym of termssuch as including, containing, or having, is used herein to describe andclaim the invention, the present invention, or embodiments thereof, mayalternatively be described using alternative terms such as “consistingof” or “consisting essentially of.”

Unless stated otherwise, the terms “a” and “an” and “the” and similarreferences used in the context of describing a particular embodiment ofthe application (especially in the context of claims) can be construedto cover both the singular and the plural. The recitation of ranges ofvalues herein is merely intended to serve as a shorthand method ofreferring individually to each separate value falling within the range.Unless otherwise indicated herein, each individual value is incorporatedinto the specification as if it were individually recited herein. Allmethods described herein can be performed in any suitable order unlessotherwise indicated herein or otherwise clearly contradicted by context.The use of any and all examples, or exemplary language (for example,“such as”) provided with respect to certain embodiments herein isintended merely to better illuminate the application and does not pose alimitation on the scope of the embodiments otherwise claimed. Theabbreviation, “e.g.” is derived from the Latin exempli gratia, and isused herein to indicate a non-limiting example. Thus, the abbreviation“e.g.” is synonymous with the term “for example.” No language in thespecification should be construed as indicating any non-claimed elementessential to the practice of the application.

“Optional” or “optionally” means that the subsequently describedcircumstance may or may not occur, so that the description includesinstances where the circumstance occurs and instances where it does not.

As stated above, there is a need in the art for methods and systems forreducing and/or removing the amount of oxygen from an oxidativedehydrogenation product and/or a product stream of an oxidativedehydrogenation process. In order to meet this need, in variousembodiments of the present invention we combine at least one oxygenremoval reactor comprising at least one oxygen removal catalyst andrecover an effluent stream from the oxygen removal reactor which has areduced oxygen content as compared to the product stream of theoxidative dehydrogenation product. In other embodiments, we contact theeffluent stream in at least one absorber unit comprising at least oneoxygen absorbent.

As can be seen from the various embodiments of the invention as shown inthe Examples herein, particularly for Example 1, the total oxygenremoval is 91.14%. This is compared to Comparative Example 1, where thetotal oxygen removal is 44.00%. As can be seen from comparing Example 1and Comparative Example 1, neither utilize an absorber unit comprisingan oxygen absorbent.

Furthermore, as can be seen from the various embodiments of theinvention as shown in the Examples herein, particularly for Example 2,the total oxygen removal is 99.53% when an effluent from an oxygenremoval reactor is fed to an oxygen absorber unit.

Furthermore, as can be seen from the various embodiments of theinvention as shown in the Examples herein, particularly for Examples2-4, the total oxygen removal is in the range of 96.47 to 99.53%.

Referring now to FIGS. 1-3, various oxygen removal systems for removingoxygen from a product stream of an ODH process according to embodimentsof the present invention are illustrated, where like numerals representlike parts.

Referring now to FIG. 1, a product stream from an oxidativedehydrogenation process 6 is fed to a heater 1 through a heater inlet I1via a supply line 7. The heated product stream is then fed into at leastone oxygen removal reactor 2 via a reactor inlet I2. The oxygen removalreactor 2 comprises a catalyst bed 2 a providing for removal of at leasta portion of the oxygen from the heated ODH product stream. Effluentfrom the oxygen removal reactor 2 is fed into a cooler 3 via a coolerinlet I3. The cooled effluent is fed into at least one absorber unit 4via an absorber inlet I4. The absorber unit 4 comprises an absorbent ora molecular sieve bed 4 a providing for removal of at least a portion ofthe oxygen from the cooled effluent from the oxygen removal reactor 2.Effluent from the absorber unit 4 is recovered via the absorber unitoutlet O1.

Referring now to FIG. 2, a product stream from an oxidativedehydrogenation process 6 is passed through a heat recovery exchanger 5via a supply line 7. After passing through the heat recovery exchanger 5the product stream from the oxidative dehydrogenation process 6 is fedto a heater 1 through a heater inlet I1. The heated product stream isthen fed into at least one oxygen removal reactor 2 via a reactor inletI2. The oxygen removal reactor 2 comprises a catalyst bed 2 a providingfor removal of at least a portion of the oxygen from the heated ODHproduct stream. Effluent from the oxygen removal reactor 2 is passedthrough the heat recovery exchanger 5 and then into a cooler 3 via acooler inlet I3. The cooled effluent is fed into at least one absorberunit 4 via an absorber inlet I4. The absorber unit 4 comprises anabsorbent or a molecular sieve bed 4 a providing for removal of at leasta portion of the oxygen from the cooled effluent from the oxygen removalreactor 2. Effluent from the absorber unit 4 is recovered via theabsorber unit outlet O1.

Referring to FIG. 3, a product stream from an oxidative dehydrogenationprocess 6 containing oxygen and at least two alkanes, at least twoalkenes, carbon monoxide, carbon dioxide, and water is passed through aheater 1 through a heated inlet I1 via supply line 7. The heated productstream is then fed into at least one oxygen removal reactor 2 via areactor inlet I2. The oxygen removal reactor 2 comprises a catalyst bed2 a providing for removal of at least a portion of the oxygen from theheated ODH product stream. Effluent from the oxygen removal reactor 2 isfed into a cooler 3 via a cooler inlet I3. By utilizing a Mn-basedcatalyst in catalyst bed 2 a of reactor 2, the process can be performedwithout removing water from the incoming heated product stream, andstill yield significant oxygen removal in the oxygen removal reactor 2.

Other useful flow schemes are contemplated via various embodiments ofthe present invention.

In various embodiments, equipment that may be used in the methods(processes) and/or systems described herein includes conventionalreactors, piping, etc. The equipment is amenable and economical for usein process plants that can be either large or small.

Oxidative Dehydrogenation Product Stream

In various embodiments the systems and/or methods of the presentinvention comprise a supply line for transporting a product stream of anoxidative dehydrogenation process (e.g., a product stream from anoxidative dehydrogenation reactor) to an oxygen removal system and/or toat least one oxygen removal reactor (e.g., at least one oxygen removalreactor of the oxygen removal system).

In various embodiments the systems and/or methods of the presentinvention, a product stream of an oxidative dehydrogenation processcomprises at least one alkane, at least one alkene, oxygen, and carbonmonoxide. In some embodiments, the at least one alkene is selected fromC₂-C₅ alkenes. In some embodiments, the at least one alkene is ethylene.In some embodiments the at least one alkane is ethane.

In some embodiments, the product stream of an oxidative dehydrogenationprocess further comprises carbon dioxide. In some embodiments, theproduct stream of an oxidative dehydrogenation process further comprisespropane.

In some embodiments the oxygen present in the oxidative dehydrogenationproduct stream is present in a baseline amount of 1,000 ppmv to 10,000ppmv. In some embodiments, the product stream of an oxidativedehydrogenation process has a baseline oxygen content of 1,000 ppmv to8,000 ppmv. In some embodiments, the product stream of an oxidativedehydrogenation process has a baseline oxygen content of 1,000 ppmv to5,000 ppmv.

In some embodiments, the product stream has a gas hourly space velocity(GHSV) of 100 to 12,000 hr⁻¹ in the at least one oxygen removal reactor.In some embodiments, the product stream has a gas hourly space velocity(GHSV) of 1,000 to 10,000 hr⁻¹ in the at least one oxygen removalreactor. In some embodiments, the product stream has a gas hourly spacevelocity (GHSV) of 4,000 to 9,000 hr⁻¹ in the at least one oxygenremoval reactor.

Heater

In various embodiments the oxygen removal system of the presentinvention comprises a heater for heating the product stream from theoxidative dehydrogenation process. In some embodiments the heatercomprises a heater inlet.

In various embodiments, the product stream is heated before being fedinto the at least one oxygen removal reactor. In various embodiments,the product stream is heated before contacting the product stream withat least one oxygen removal catalyst. In some embodiments, the heatingof the product stream is effected at a temperature of 100° C. to 600° C.In some embodiments, the heating of the product stream is effected at atemperature of 125° C. to 500° C. In some embodiments, the heating ofthe product stream is effected at a temperature of 150° C. to 400° C.

In some embodiments, the heater is connected to the supply line fortransporting the product stream to the at least one oxygen removalreactor. In some embodiments, the heater is connected to the at leastone oxygen removal reactor. In some embodiments, the heater is connectedto and upstream from the at least one oxygen removal reactor.

Heat Recovery Exchanger

In various embodiments the oxygen removal system of the presentinvention further comprises a heat recovery exchanger. In someembodiments, the heat recovery exchanger may be used for optionallyheating the product stream. In some embodiments, the heat recoveryexchanger may be used for optionally heating the product stream byutilizing recoverable heat from the effluent stream from the oxygenremoval reactors. In some embodiments, the heater and the heat recoverexchanger are used for heating the product stream. In some embodiments,the heater and the heat recovery exchanger are used for heating theproduct stream before contacting the product stream with the at leastone oxygen removal catalyst.

In some embodiments, the heating of the product stream is effected at atemperature of 80° C. to 350° C. In some embodiments, the heating of theproduct stream is effected at a temperature of 100° C. to 250° C. Insome embodiments, the heating of the product stream is effected at atemperature of 150° C. to 200° C.

In various embodiments, the heat recovery exchanger is connected to thesupply line for transporting the product stream of the oxidativedehydrogenation process to the at least one oxygen removal reactor. Insome embodiments, the heat recovery exchanger is connected to theheater. In some embodiments, the heat recovery exchanger is connected toand upstream from the heater. In some embodiments, the heat recoveryexchanger is connected to the at least one oxygen removal reactor. Insome embodiments, the heat recovery exchanger is connected to anddownstream from the at least one oxygen removal reactor. In someembodiments, the heat recovery exchanger is connected to the cooler. Insome embodiments, the heat recovery exchanger is connected to andupstream from the cooler.

Oxygen Removal Reactor(s)

In various embodiments the oxygen removal system of the presentinvention provides at least one oxygen removal reactor for removing atleast a portion of oxygen from a product stream of an oxidativedehydrogenation process, wherein the oxygen removal reactors comprise atleast at least one oxygen removal catalyst. In further embodiments, theoxygen removal reactors further comprise an inlet for the productstream, and an outlet for the effluent from the oxygen removal reactors.In some embodiments, the effluent from the oxygen removal reactors is afirst effluent stream from the at least one oxygen removal reactor. Insome embodiments, the oxygen removal reactors comprise an oxygen removalinlet.

In various embodiments the present invention provides an oxygen removalsystem comprising at least one oxygen removal reactor for preparing afirst effluent stream, wherein the at least one oxygen removal reactorcomprise at least one oxygen removal catalyst, an inlet for the productstream, and an outlet for the first effluent stream, wherein the firsteffluent stream has a first oxygen content, wherein the first oxygencontent of the first effluent stream is reduced compared to the baselineoxygen content of the product stream (i.e., the product stream from theoxidative dehydrogenation process).

In some embodiments, the effluent stream from the oxygen removalreactors comprises oxygen. In some embodiments, the effluent stream fromthe oxygen removal reactors has an oxygen content, wherein the oxygencontent in the effluent stream from the oxygen removal reactors isreduced compared to the baseline oxygen content of the product stream(i.e., the product stream from the oxidative dehydrogenation process).

In some embodiments, the oxygen removal reactors, oxygen removalreaction temperature, and/or oxygen removal catalysts are at atemperature of 100° C. to 600° C. In some embodiments, the oxygenremoval reactors, oxygen removal reaction temperature, and/or oxygenremoval catalysts are at a temperature of 125° C. to 500° C. In someembodiments, the oxygen removal reactors, oxygen removal reactiontemperature, and/or oxygen removal catalysts are at a temperature of150° C. to 400° C.

In various embodiments the effluent stream from the oxygen removalreactors comprises oxygen, wherein the amount of oxygen in the effluentstream (i.e., the oxygen content in the effluent stream) is 100 to 5,000parts per million by volume (ppmv). In some embodiments, the effluentstream from the oxygen removal reactors comprises oxygen, wherein theamount of oxygen in the effluent stream is 100 to 2,000 parts permillion by volume (ppmv). In some embodiments, the effluent stream fromthe oxygen removal reactors comprises oxygen, wherein the amount ofoxygen in the effluent stream is 100 to 1,000 parts per million byvolume (ppmv).

In some embodiments, the effluent stream from the oxygen removalreactors has a gas hourly space velocity (GHSV) of 100 to 12,000 hr⁻¹,preferably 4,000 to 9,000 hr⁻¹. In some embodiments, the effluent streamfrom the oxygen removal reactors has a gas hourly space velocity (GHSV)of 1,000 to 10,000 hr⁻¹, preferably 4,000 to 9,000 hr⁻¹, and is fed intothe at least one absorber unit.

In some embodiments, the effluent stream from the oxygen removalreactors has a temperature of 100° C. to 600° C. before being cooled,for example, by passing through the cooler. In some embodiments, theeffluent stream from the oxygen removal reactors has a temperature of125° C. to 500° C. In some embodiments, the effluent stream from theoxygen removal reactors has a temperature of 150° C. to 400° C. In someembodiments, the effluent stream from the oxygen removal reactor has atemperature of 150° C. to 250° C.

In various embodiments the oxygen removal system of the presentinvention comprises more than one oxygen removal reactor in parallel,allowing oxygen removal catalyst or an oxygen removal catalyst bed inone oxygen removal reactor to be changed while the other oxygen removalreactor is on-line, without shutting down the oxidative dehydrogenationreactor.

In various embodiments the systems and/or methods of the presentinvention comprise at least one oxygen removal reactor. In variousembodiments the systems and/or methods of the present invention compriseat least two oxygen removal reactors.

In various embodiments, the at least one oxygen removal reactor isconnected to the heater. In various embodiments, the at least one oxygenremoval reactor is connected to and downstream from the heater.

Cooler

In various embodiments the oxygen removal system of the presentinvention comprises a cooler for cooling the effluent stream from theoxygen removal reactors. In some embodiments, the effluent stream is afirst effluent stream. In various embodiments the oxygen removal systemof the present invention comprises a cooler for cooling the firsteffluent stream from the oxygen removal reactors. In some embodimentsthe cooler comprises a cooler inlet.

In various embodiments the effluent stream from the oxygen removalreactors is cooled before being fed into at least one absorber unit. Insome embodiments, the effluent stream is a first effluent stream. Invarious embodiments the effluent stream from the oxygen removal reactorsis effected at a temperature of 25° C. to 130° C. In some embodiments,the cooling of the first effluent stream is effected at a temperature of25° C. to 100° C. In some embodiments, the cooling of the first effluentstream is effected at a temperature of 25° C. to 80° C. In someembodiments, the cooling of the first effluent stream is effected at atemperature of 40° C. to 50° C.

In various embodiments, the cooler is connected to the at least oneoxygen removal reactor. In various embodiments, the cooler is connectedto and downstream from the at least one oxygen removal reactor.

Absorber Units

In various embodiments the oxygen removal system of the presentinvention comprises at least one absorber unit for removing at least aportion of oxygen from an effluent stream from at least one oxygenremoval reactor, wherein the absorber units comprise at least at leastone oxygen absorbent. In further embodiments, the absorber units furthercomprise an inlet for the effluent stream from the oxygen removalreactors, and an outlet for the effluent from the absorber units. Insome embodiments, the effluent from the oxygen removal reactors is afirst effluent stream. In some embodiments, the effluent stream from theabsorber units is a second effluent stream. In some embodiments, theabsorber units comprise an absorber unit inlet. In some embodiments theabsorber units comprise an absorber unit outlet. In some embodiments,the flow in the absorber unit(s) has a gas hourly space velocity (GHSV)of 3,000 to 4,000 in the at least one absorber unit.

In various embodiments the present invention provides an oxygen removalsystem comprising at least one absorber unit for preparing a secondeffluent stream, wherein the at least one absorber unit comprise atleast one oxygen absorbent, an inlet for the first effluent stream, andan outlet for the second effluent stream, wherein the second effluentstream has a second oxygen content, wherein the second oxygen content ofthe second effluent stream is reduced compared to the oxygen content ofthe first effluent stream (i.e., the effluent stream from the oxygenremoval reactors).

In various embodiments the effluent stream from the absorber unitcomprises oxygen. In various embodiments, the effluent stream from theabsorber units has an oxygen content, wherein the oxygen content in theeffluent stream from the absorber units is reduced compared to theoxygen content of the effluent stream from the oxygen removal reactors.

In various embodiments the effluent stream from the absorber unitcomprises oxygen, wherein the amount of oxygen in the effluent stream(i.e., the oxygen content in the effluent stream) is 1-4,000 parts permillion by volume (ppmv). In some embodiments, the effluent stream fromthe absorber unit comprises oxygen, wherein the amount of oxygen in theeffluent stream is 1-2,000 parts per million by volume (ppmv). In someembodiments, the effluent stream from the absorber unit comprisesoxygen, wherein the amount of oxygen in the effluent stream is 1-500parts per million by volume (ppmv).

In some embodiments, the effluent stream from the absorber unitcomprises oxygen, wherein the amount of oxygen in the effluent stream is0, 0-1, 1, 1-2, 1-3, 1-4, 1-5, 1-6, 1-7, 1-8, 1-9, 1-10, 1-11, 1-12,1-13, 1-14, 1-15, 1-16, 1-17, 1-18, 1-19, 1-20, 1-21, 1-22, 1-23, 1-24,1-25, 1-26, 1-27, 1-28, 1-29, 1-30, 1-31, 1-32, 1-33, 1-34, 1-35, 1-36,1-37, 1-38, 1-39, 1-40, 1-50, 1-60, 1-70, 1-80, 1-90, 1-100, 1-150,1-200, 1-250, 1-300, 1-350, 1-400, 1-450, 1-500, 1-550, 1-600, 1-650,1-700, 1-750, 1-800, 1-850, 1-900, 1-950, 1-1000, 1-1050, 1-1100,1-1150, 1-1200, 1-1250, 1-1300, 1-1350, 1-1400, 1-1450, 1-1500, 1-1550,1-1600, 1-1650, 1-1700, 1-1750, 1-1800, 1-1850, 1-1900, 1-1950, 1-2000,1-2050, 1-2100, 1-2150, 1-2200, 1-2250, 1-2300, 1-2350, 1-2400, 1-2450,1-2500, 1-2550, 1-2600, 1-2650, 1-2700, 1-2750, 1-2800, 1-2850, 1-2900,1-2950, 1-3000, 1-3050, 1-3100, 1-3150, 1-3200, 1-3250, 1-3300, 1-3350,1-3400, 1-3450, 1-3500, 1-3550, 1-3600, 1-3650, 1-3700, 1-3750, 1-3800,1-3850, 1-3900, 1-3950, 1-4000, 1-4050, 1-4100, 1-4150, 1-4200, 1-4250,1-4300, 1-4350, 1-4400, 1-4450, 1-4500, 1-4550, 1-4500, 1-4550, 1-4600,1-4650, 1-4600, 1-4650, 1-4700, 1-4750, 1-4800, 1-4850, 1-4900, 1-4950,1-5000, 1-5050, 1-5100, and 1-5150 parts per million by volume (ppmv).

In some embodiments, the effluent stream from the absorber unitcomprises oxygen, wherein the amount of oxygen in the effluent stream is4000-3950, 4000-3900, 4000-3850, 4000-3800, 4000-3750, 4000-3700,4000-3650, 4000-3600, 4000-3550, 4000-3500, 4000-3450, 4000-3400,4000-3350, 4000-3300, 4000-3250, 4000-3200, 4000-3150, 4000-3100,4000-3050, 4000-3000, 4000-2950, 4000-2900, 4000-2850, 4000-2800,4000-2750, 4000-2700, 4000-2650, 4000-2600, 4000-2550, 4000-2500,4000-2450, 4000-2400, 4000-2350, 2350, 4000-2300, 4000-2250, 4000-2200,4000-2150, 4000-2100, 4000-2050, 4000-2000, 4000-1950, 4000-1900,4000-1850, 4000-1800, 4000-1750, 4000-1700, 4000-1650, 4000-1600,4000-1550, 4000-1500, 4000-1450, 4000-1400, 4000-1350, 4000-1300,4000-1250, 4000-1200, 4000-1150, 4000-1100, 4000-1050, 4000-1000,4000-950, 4000-900, 4000-850, 4000-800, 4000-750, 4000-700, 4000-650,4000-600, 4000-550, 4000-500, 4000-450, 4000-400, 4000-350, 4000-300,4000-250, 4000-200, 4000-150, 4000-100, 4000-90, 4000-80, 4000-70,4000-60, 4000-50, 4000-40, 4000-30, 4000-20, 4000-10, 4000-9, 4000-8,4000-7, 4000-6, 4000-5, 4000-4, 4000-3, 4000-2, 4000-1, or 4000-0 partsper million by volume (ppmv).

In various embodiments the effluent stream from the absorber unitcomprises oxygen, a ratio of the second oxygen content of the secondeffluent stream relative to the first oxygen content of the firsteffluent stream is less than 15%. In some embodiments, a ratio of thesecond oxygen content of the second effluent stream relative to thefirst oxygen content of the first effluent stream is less than 10%, thatis, the oxygen contained in the product stream can be further removed bythe at least one absorber unit. In some embodiments, the ratio of thesecond oxygen content of the second effluent stream relative to thefirst oxygen content of the first effluent stream is less than 5%.

In some embodiments, the ratio of the second oxygen content of thesecond effluent stream relative to the first oxygen content of the firsteffluent stream is less than 15.0%, less than 14.9%, less than 14.8%,less than 14.7%, less than 14.6%, less than 14.5%, less than 14.4%, lessthan 14.3%, less than 14.2%, less than 14.1%, less than 14.0%, less than13.9%, less than 13.8%, less than 13.7%, less than 13.6%, less than13.5%, less than 13.4%, less than 13.3%, less than 13.2%, less than13.1%, less than 13.0%, less than 12.9%, less than 12.8%, less than12.7%, less than 12.6%, less than 12.5%, less than 12.4%, less than12.3%, less than 12.2%, less than 12.1%, less than 12.0%, less than11.9%, less than 11.8%, less than 11.7%, less than 11.6%, less than11.5%, less than 11.4%, less than 11.3%, less than 11.2%, less than11.1%, less than 11.0%, less than 10.9%, less than 10.8%, less than10.7%, less than 10.6%, less than 10.5%, less than 10.4%, less than10.3%, less than 10.2%, less than 10.1%, less than 10.0%, less than9.9%, less than 9.8%, less than 9.7%, less than 9.6%, less than 9.5%,less than 9.4%, less than 9.3%, less than 9.2%, less than 9.1%, lessthan 9.0%, less than 8.9%, less than 8.8%, less than 8.7%, less than8.6%, less than 8.5%, less than 8.4%, less than 8.3%, less than 8.2%,less than 8.1%, less than 8.0%, less than 7.9%, less than 7.8%, lessthan 7.7%, less than 7.6%, less than 7.5%, less than 7.4%, less than7.3%, less than 7.2%, less than 7.1%, less than 7.0%, less than 6.9%,less than 6.8%, less than 6.7%, less than 6.6%, less than 6.5%, lessthan 6.4%, less than 6.3%, less than 6.2%, less than 6.1%, less than6.0%, less than 5.9%, less than 5.8%, less than 5.7%, less than 5.6%,less than 5.5%, less than 5.4%, less than 5.3%, less than 5.2%, lessthan 5.1%, less than 5.0%, less than 4.9%, less than 4.8%, less than4.7%, less than 4.6%, less than 4.5%, less than 4.4%, less than 4.3%,less than 4.2%, less than 4.1%, less than 4.0%, less than 3.9%, lessthan 3.8%, less than 3.7%, less than 3.6%, less than 3.5%, less than3.4%, less than 3.3%, less than 3.2%, less than 3.1%, less than 3.0%,less than 2.9%, less than 2.8%, less than 2.7%, less than 2.6%, lessthan 2.5%, less than 2.4%, less than 2.3%, less than 2.2%, less than2.1%, less than 2.0%, less than 1.9%, less than 1.8%, less than 1.7%,less than 1.6%, less than 1.5%, less than 1.4%, less than 1.3%, lessthan 1.2%, less than 1.1%, less than 1.0%, less than 0.9%, less than0.8%, less than 0.7%, less than 0.6%, or less than 0.5%.

In some embodiments, the ratio of the second oxygen content of thesecond effluent stream relative to the first oxygen content of the firsteffluent stream is 15.0% to 0%, 15.0% to 0.1%, 14.9% to 0%, 14.9% to0.1%, 14.9% to 0.2%, 14.9% to 0.3%, 14.9% to 0.4%, 14.9% to 0.5%, 14.9%to 0.6%, 14.9% to 0.7%, 14.9% to 0.8%, 14.9% to 0.9%, 14.9% to 1.0%,14.9% to 1.1%, 14.9% to 1.2%, 14.9% to 1.3%, 14.9% to 1.4%, 14.9% to1.5%, 14.9% to 1.6%, 14.9% to 1.7%, 14.9% to 1.8%, 14.9% to 1.9%, 14.9%to 2.0%, 14.9% to 2.1%, 14.9% to 2.2%, 14.9% to 2.3%, 14.9% to 2.4%,14.9% to 2.5%, 14.9% to 2.6%, 14.9% to 2.7%, 14.9% to 2.8%, 14.9% to2.9%, 14.9% to 3.0%, 14.9% to 3.1%, 14.9% to 3.2%, 14.9% to 3.3%, 14.9%to 3.4%, 14.9% to 3.5%, 14.9% to 3.6%, 14.9% to 3.7%, 14.9% to 3.8%,14.9% to 3.9%, 14.9% to 4.0%, 14.9% to 4.1%, 14.9% to 4.2%, 14.9% to4.3%, 14.9% to 4.4%, 14.9% to 4.5%, 14.9% to 4.6%, 14.9% to 4.7%, 14.9%to 4.8%, 14.9% to 4.9%, 14.9% to 5.0%, 14.9% to 5.1%, 14.9% to 5.2%,14.9% to 5.3%, 14.9% to 5.4%, 14.9% to 5.5%, 14.9% to 5.6%, 14.9% to5.7%, 14.9% to 5.8%, 14.9% to 5.9%, 14.9% to 6.0%, 14.9% to 6.1%, 14.9%to 6.2%, 14.9% to 6.3%, 14.9% to 6.4%, 14.9% to 6.5%, 14.9% to 6.6%,14.9% to 6.7%, 14.9% to 6.8%, 14.9% to 6.9%, 14.9% to 7.0%, 14.9% to7.1%, 14.9% to 7.2%, 14.9% to 7.3%, 14.9% to 7.4%, 14.9% to 7.5%, 14.9%to 7.6%, 14.9% to 7.7%, 14.9% to 7.8%, 14.9% to 7.9%, 14.9% to 8.0%,14.9% to 8.1%, 14.9% to 8.2%, 14.9% to 8.3%, 14.9% to 8.4%, 14.9% to8.5%, 14.9% to 8.6%, 14.9% to 8.7%, 14.9% to 8.8%, 14.9% to 8.9%, 14.9%to 9.0%, 14.9% to 9.1%, 14.9% to 9.2%, 14.9% to 9.3%, 14.9% to 9.4%,14.9% to 9.5%, 14.9% to 9.6%, 14.9% to 9.7%, 14.9% to 9.8%, 14.9% to9.9%, 14.9% to 10.0%, 14.9% to 10.1%, 14.9% to 10.2%, 14.9% to 10.3%,14.9% to 10.4%, 14.9% to 10.5%, 14.9% to 10.6%, 14.9% to 10.7%, 14.9% to10.8%, 14.9% to 10.9%, 14.9% to 11.0%, 14.9% to 11.1%, 14.9% to 11.2%,14.9% to 11.3%, 14.9% to 11.4%, 14.9% to 11.5%, 14.9% to 11.6%, 14.9% to11.7%, 14.9% to 11.8%, 14.9% to 11.9%, 14.9% to 12.0%, 14.9% to 12.1%,14.9% to 12.2%, 14.9% to 12.3%, 14.9% to 12.4%, 14.9% to 12.5%, 14.9% to12.6%, 14.9% to 12.7%, 14.9% to 12.8%, 14.9% to 12.9%, 14.9% to 13.0%,14.9% to 13.1%, 14.9% to 13.2%, 14.9% to 13.3%, 14.9% to 13.4%, 14.9% to13.5%, 14.9% to 13.6%, 14.9% to 13.7%, 14.9% to 13.8%, 14.9% to 13.9%,14.9% to 14.0%, 14.9% to 14.1%, 14.9% to 14.2%, 14.9% to 14.3%, 14.9% to14.4%, 14.9% to 14.5%, 14.9% to 14.6%, 14.9% to 14.7%, or 14.9% to14.8%.

In some embodiments, the ratio of the second oxygen content of thesecond effluent stream relative to the first oxygen content of the firsteffluent stream is 0.1% to 14.9%, 0.1% to 14.8%, 0.1% to 14.7%, 0.1% to14.6%, 0.1% to 14.5%, 0.1% to 14.4%, 0.1% to 14.3%, 0.1% to 14.2%, 0.1%to 14.1%, 0.1% to 14.0%, 0.1% to 13.9%, 0.1% to 13.8%, 0.1% to 13.7%,0.1% to 13.6%, 0.1% to 13.5%, 0.1% to 13.4%, 0.1% to 13.3%, 0.1% to13.2%, 0.1% to 13.1%, 0.1% to 13.0%, 0.1% to 12.9%, 0.1% to 12.8%, 0.1%to 12.7%, 0.1% to 12.6%, 0.1% to 12.5%, 0.1% to 12.4%, 0.1% to 12.3%,0.1% to 12.2%, 0.1% to 12.1%, 0.1% to 12.0%, 0.1% to 11.9%, 0.1% to11.8%, 0.1% to 11.7%, 0.1% to 11.6%, 0.1% to 11.5%, 0.1% to 11.4%, 0.1%to 11.3%, 0.1% to 11.2%, 0.1% to 11.1%, 0.1% to 11.0%, 0.1% to 10.9%,0.1% to 10.8%, 0.1% to 10.7%, 0.1% to 10.6%, 0.1% to 10.5%, 0.1% to10.4%, 0.1% to 10.3%, 0.1% to 10.2%, 0.1% to 10.1%, 0.1% to 10.0%, 0.1%to 9.9%, 0.1% to 9.8%, 0.1% to 9.7%, 0.1% to 9.6%, 0.1% to 9.5%, 0.1% to9.4%, 0.1% to 9.3%, 0.1% to 9.2%, 0.1% to 9.1%, 0.1% to 9.0%, 0.1% to8.9%, 0.1% to 8.8%, 0.1% to 8.7%, 0.1% to 8.6%, 0.1% to 8.5%, 0.1% to8.4%, 0.1% to 8.3%, 0.1% to 8.2%, 0.1% to 8.1%, 0.1% to 8.0%, 0.1% to7.9%, 0.1% to 7.8%, 0.1% to 7.7%, 0.1% to 7.6%, 0.1% to 7.5%, 0.1% to7.4%, 0.1% to 7.3%, 0.1% to 7.2%, 0.1% to 7.1%, 0.1% to 7.0%, 0.1% to6.9%, 0.1% to 6.8%, 0.1% to 6.7%, 0.1% to 6.6%, 0.1% to 6.5%, 0.1% to6.4%, 0.1% to 6.3%, 0.1% to 6.2%, 0.1% to 6.1%, 0.1% to 6.0%, 0.1% to5.9%, 0.1% to 5.8%, 0.1% to 5.7%, 0.1% to 5.6%, 0.1% to 5.5%, 0.1% to5.4%, 0.1% to 5.3%, 0.1% to 5.2%, 0.1% to 5.1%, 0.1% to 5.0%, 0.1% to4.9%, 0.1% to 4.8%, 0.1% to 4.7%, 0.1% to 4.6%, 0.1% to 4.5%, 0.1% to4.4%, 0.1% to 4.3%, 0.1% to 4.2%, 0.1% to 4.1%, 0.1% to 4.0%, 0.1% to3.9%, 0.1% to 3.8%, 0.1% to 3.7%, 0.1% to 3.6%, 0.1% to 3.5%, 0.1% to3.4%, 0.1% to 3.3%, 0.1% to 3.2%, 0.1% to 3.1%, 0.1% to 3.0%, 0.1% to2.9%, 0.1% to 2.8%, 0.1% to 2.7%, 0.1% to 2.6%, 0.1% to 2.5%, 0.1% to2.4%, 0.1% to 2.3%, 0.1% to 2.2%, 0.1% to 2.1%, 0.1% to 2.0%, 0.1% to1.9%, 0.1% to 1.8%, 0.1% to 1.7%, 0.1% to 1.6%, 0.1% to 1.5%, 0.1% to1.4%, 0.1% to 1.3%, 0.1% to 1.2%, 0.1% to 1.1%, 0.1% to 1.0%, 0.1% to0.9%, 0.1% to 0.8%, 0.1% to 0.7%, 0.1% to 0.6%, 0.1% to 0.5%, 0.1% to0.4%, 0.1% to 0.3%, or 0.1% to 0.2%.

In some embodiments, the absorber units and/or oxygen absorbents are ata temperature of 25° C. to 130° C. In some embodiments, the absorberunits and/or oxygen absorbents are at a temperature of 25° C. to 100° C.In some embodiments, the absorber units and/or oxygen absorbents are ata temperature of 25° C. to 80° C. In some embodiments, the absorberunits are at a temperature of 40° C. to 50° C.

In various embodiments the oxygen removal system of the presentinvention comprises more than one absorber unit in parallel, allowingoxygen absorbent or an oxygen absorbent bed in one absorber unit to bechanged while the other absorber unit is on-line, without shutting downthe oxidative dehydrogenation reactor.

In various embodiments, the systems and/or methods of the presentinvention comprise at least one absorber unit. In various embodimentsthe systems and/or methods of the present invention comprise at leasttwo absorber units.

In various embodiments, the at least one absorber unit is connected tothe cooler. In various embodiments, the at least one absorber unit isconnected to and downstream from the cooler.

Oxygen Removal Catalysts

In various embodiments of the present invention, the oxygen removalcatalyst comprises at least one metal selected from Fe, Ru, Os, Co, Rh,Ir, Ni, Pd, Pt, and Mn. In various embodiments of the present invention,the oxygen removal catalyst comprises Pd. In other embodiments of thepresent invention, the oxygen removal catalyst comprises an Mn-basedcatalyst. In other embodiments of the present invention, the oxygenremoval catalyst comprises MnOx. In various embodiments, the oxygenremoval catalyst can be supported on a substrate. In variousembodiments, the at least one metal can be supported on a substrate. Invarious embodiments, the oxygen removal catalyst comprises Pd on anAl₂O₃ carrier. In various embodiments, the oxygen removal catalystcomprises a mixed oxide of Mn with at least one other metal selectedfrom the group consisting of Cu, Ce, and Al. A non-limiting example ofan oxygen removal catalyst is commercially available as BASF R0-20.

In some embodiments, the oxygen removal catalyst is in the form of acatalyst bed.

Oxygen Absorbents

In some embodiments of this disclosure, the effluent from the oxygenremoval reactor need not be passed to an oxygen absorbent reactor, butmay be cooled and recovered as shown by the apparatus of FIG. 3 andExample 1. In others embodiments of the present invention, the oxygenabsorbent comprises at least one metal selected from Cu, Ag, Au, Zn, Cd,and Hg. In various embodiments of the present invention, the oxygenabsorbent comprises Cu. In various embodiments, the oxygen absorbentcomprises CuO. In various embodiments, the oxygen absorbent comprisesCuO and ZnO. Non-limiting examples of an oxygen absorbent arecommercially available as PuriStar® R3-16.

In some embodiments, the oxygen absorbent is in the form of an absorbentbed.

Molecular Sieves

In various embodiments of the present invention, the oxygen absorbentcomprises a molecular sieve. In some embodiments, the molecular sieve isselected from a type 3A, a type 4A, and any combination thereof. Anon-limiting example of a molecular sieve is commercially available asUOP Type-3A.

In some embodiments, the molecular sieve is in the form of a molecularsieve bed.

In various embodiments, the present invention provides a method forremoving oxygen from a product stream of an oxidative dehydrogenationprocess, comprising: contacting the product stream of the oxidativedehydrogenation process with at least one oxygen removal catalyst in atleast one oxygen removal reactor under conditions effective to remove atleast a portion of the oxygen from the product stream, wherein theproduct stream has a baseline oxygen content; recovering a firsteffluent stream from the at least one oxygen removal reactor, whereinthe first effluent stream has a first oxygen content, wherein the firstoxygen content of the first effluent stream is reduced compared to thebaseline oxygen content of the product stream; contacting the firsteffluent stream with at least one oxygen absorbent in at least oneabsorber unit under conditions effective to remove at least a portion ofthe oxygen from the first effluent stream; and recovering a secondeffluent stream from the at least one absorber unit, wherein the secondeffluent stream has a second oxygen content, wherein the second oxygencontent of the second effluent stream is reduced compared to the firstoxygen content of the first effluent stream.

In various embodiments, the present invention provides an oxygen removalsystem for removing oxygen from a product stream of an oxidativedehydrogenation process, comprising: at least one oxygen removal reactorfor preparing a first effluent stream, wherein the at least one oxygenremoval reactor comprises at least one oxygen removal catalyst, an inletfor the product stream, and an outlet for the first effluent stream; asupply line for transporting the product stream of the oxidativedehydrogenation process to the at least one oxygen removal reactor,wherein the product stream has a baseline oxygen content; a heater forheating the product stream; a cooler for cooling the first effluentstream; and at least one absorber unit for preparing a second effluentstream, wherein the at least one absorber unit comprises at least oneoxygen absorbent, an inlet for the first effluent stream, and an outletfor the second effluent stream; herein the first effluent stream has afirst oxygen content, wherein the first oxygen content of the firsteffluent stream is reduced compared to the baseline oxygen content ofthe product stream; wherein the second effluent stream has a secondoxygen content, wherein the second oxygen content of the second effluentstream is reduced compared to the first oxygen content of the firsteffluent stream; wherein the heater is connected to the supply line fortransporting the product stream to the at least one oxygen removalreactor; wherein the at least one oxygen removal reactor is connected toand downstream from the heater; wherein the cooler is connected to anddownstream from the at least one oxygen removal reactor; and wherein theat least one absorber unit is connected to and downstream from thecooler.

In some embodiments, the oxygen removal system further comprises a heatrecovery exchanger for optionally heating the product stream byutilizing recoverable heat from the first effluent stream, wherein heatrecovery exchanger is: (i) connected to and downstream from the supplyline for transporting the product stream of the oxidativedehydrogenation process to the at least one oxygen removal reactor; (ii)connected to and upstream from the heater; (iii) connected to anddownstream from the at least one oxygen removal reactor; and (iv)connected to and upstream from the cooler; wherein the at least oneoxygen removal reactor is connected to and downstream from the heater;and wherein, the at least one absorber unit is connected to anddownstream from the cooler.

Some embodiments of the present invention can be defined as any of thefollowing numbered paragraphs:

-   -   1. A method of removing oxygen from an oxygen containing product        stream of an oxidative dehydrogenation process, comprising:        contacting the product stream of the oxidative dehydrogenation        process with at least one oxygen removal catalyst in at least        one oxygen removal reactor; wherein the product stream has a        baseline oxygen content; and, recovering a first effluent stream        from the at least one oxygen removal reactor, wherein the first        effluent stream has a first oxygen content, wherein the first        oxygen content of the first effluent stream is reduced as        compared to the baseline oxygen content of the product stream;        wherein the product stream comprises at least two alkenes, at        least two alkanes, carbon monoxide, carbon dioxide, water and        oxygen; and wherein the at least one oxygen removal catalyst is        a Mn-based oxygen removal catalyst.    -   2. The method of paragraph 1, wherein the contacting step with        the Mn-based oxygen removal catalyst is conducted at a first        elevated temperature and for a time sufficient to remove at        least 72.5% of the baseline oxygen content.    -   3. The method of paragraph 1, further comprising the step of        contacting the first effluent stream with at least one oxygen        absorbent in at least one absorber unit at a second elevated        temperature after the step of recovering a first effluent stream        from the at least one oxygen removal reactor, the second        elevated temperature is lower than the first elevated        temperature, for a time sufficient to absorb oxygen from said        first effluent stream, and recovering a second effluent stream,        wherein the second effluent stream has a second oxygen content        which is reduced as compared to first oxygen content of the        first effluent stream.    -   4. The method of paragraph 2, wherein the first elevated        temperature is in a temperature range of from 150° C.-250° C.    -   5. The method of paragraph 2, wherein the step of contacting the        oxygen containing product stream comprises contacting the        product stream with the Mn-based oxygen removal catalyst in the        oxygen removal reactor is conducted at a GHSV rate in the range        of 4000-9000 hr⁻¹.    -   6. The method of paragraph 3, wherein the second elevated        temperature is in the range from 40° C. to 50° C.    -   7. The method of paragraph 3, wherein the at least one oxygen        absorbent comprises at least one metal selected from Cu, Ag, Au,        Zn, Cd, and Hg.    -   8. The method of paragraph 3, wherein the at least one oxygen        absorbent comprises a molecular sieve.    -   9. The method of paragraph 1, wherein the contacting step with        the Mn-based catalyst is conducted at a first elevated        temperature and for a time sufficient to remove greater than 90%        of the baseline oxygen content.    -   10. The method of paragraph 3, wherein the total oxygen removed        from the oxygen containing product stream of the oxidative        dehydrogenation process is greater than 96 wt. % after the        absorbent step.    -   11. The method of paragraph 1, wherein the Mn-based catalyst        comprises MnOx.    -   12. The method of paragraph 1, wherein the Mn-based catalyst        comprises a mixed oxide of Mn and at least one other metal.    -   13. The method of paragraph 1, wherein the oxygen containing        product stream from the oxidative dehydrogenation process        comprises ethylene and propylene, ethane and propane, carbon        monoxide, carbon dioxide, water and oxygen.    -   14. The method of paragraph 13, wherein the oxygen containing        product stream from the oxidative dehydrogenation process        further comprises methane.    -   15. The method of paragraph 3, wherein the recovered second        effluent stream comprises a reduced amount of carbon monoxide as        compared to the carbon monoxide content of the oxygen containing        product stream from the oxidative dehydrogenation.    -   16. The method of paragraph 3, wherein the recovered second        effluent stream comprises a water content in an amount in the        range of less than or equal to the water content of the oxygen        containing product stream from the oxidative dehydrogenation.    -   17. The method of paragraph 3, wherein the recovered second        effluent stream comprises a carbon dioxide content in an amount        in the range of less than, equal to, or more than the carbon        dioxide content of the oxygen containing product stream from the        oxidative dehydrogenation.    -   18. The method of paragraph 1, wherein the at least two alkanes        comprise methane, ethane and propane.    -   19. The method of paragraph 1, wherein the at least two alkenes        comprise ethylene and propylene.    -   20. The method of paragraph 3, wherein the total oxygen removed        from the oxygen containing product stream of the oxidative        dehydrogenation process is greater than 99 wt. % after the        absorbent step.

EXAMPLES

The following examples are not intended to limit the scope of the claimsto the invention, but are rather intended to be exemplary of certainembodiments. Any variations in the exemplified methods which occur tothe skilled artisan are intended to fall within the scope of the presentinvention.

The invention will be further explained by the following examples, whichare intended to be purely exemplary of the invention, and should not beconsidered as limiting the invention in any way. The following examplesare provided to better illustrate the claimed invention and are not tobe interpreted as limiting the scope of the invention. To the extentthat specific materials are mentioned, it is merely for purposes ofillustration and is not intended to limit the invention. One skilled inthe art may develop equivalent means or reactants without the exerciseof inventive capacity and without departing from the scope of theinvention.

Example 1

A summary of the experimental conditions and results for Example 1 andComparative Example 1 are provided. The information in Example 1corresponds to the embodiment in FIG. 3.

As can be seen from Example 1, the oxygen content at the oxygen removalreactor outlet is 452 parts per million volume (“ppmv”), as compared tothe oxygen content at the inlet of the oxygen removal reactor which was5,100 ppmv, a reduction of 91.14%. The catalyst utilized was an Mn-basedcatalyst, MnOx. Oxygen removal reactor temperature was 250° C. Flow ratethrough the oxygen removal reactor was 4180 hr⁻¹. The other componentsof the product stream present at the oxygen removal reactor inlet aremethane: 15 ppmv, ethylene: 9.17 mol %, ethane: 88.10 mol %, propane: 10ppmv, propylene: 20 ppmv, carbon monoxide (“CO”): 1.52 mol %, carbondioxide (“CO₂”): 0.58 mol % and water (“H₂O”): 0.1 mol %. Othercomponents present at the oxygen removal reactor outlet are CO: 0.59 mol%, CO₂: 0.93 mol % and water: 0.1 mol %. Total oxygen removal iscalculated at 91.14%.

Comparative Example 1 utilizes a commercially available oxygen removalcatalyst available under the trade name of BASF R0-20, available fromthe BASF corporation.

As can be seen from Comparative Example 1, the oxygen content at theoxygen removal reactor outlet is 620 parts per million volume (“ppmv”),as compared the oxygen removal reactor inlet of 1,107 ppmv, a reductionof 44.00%. Oxygen removal reactor temperature was 150° C. Flow ratethrough the oxygen removal reactor was 9000 hr⁻¹. The other componentsof the product stream present at the oxygen removal reactor inlet aremethane: 62 ppmv, ethylene: 2.91 mol %, ethane: 96.10 mol %, propane: 47ppmv, propylene: 2 ppmv, carbon monoxide (“CO”): 0.37 mol %, carbondioxide (“CO₂”): 0.26 mol % and water (“H₂O”): 0.23 mol %. Othercomponents present at the oxygen removal reactor outlet are CO: 0.26 mol%, CO₂: 0.17 mol % and water: 0.23 mol %. Total oxygen removal iscalculated at 44.00%.

As can be seen from Example 2, the components present at the oxygenremoval reactor outlet of FIG. 3, were cooled by cooler 3 to 40° C. andfed to an inlet I4 of an oxygen absorber unit 4 (FIG. 1) The oxygenabsorber unit 4 utilizes a catalyst absorber bed 4 a. In Example 2, thecatalyst in absorber bed 4 a is BASF R3-16. The absorber unit operatesat a GHSV of 3000 hr⁻¹. The effluent stream leaving absorber unit 4 a inExample 2 has the following composition: O₂:24 ppmv, CO: 0.59 mol %,CO₂: 0.93 mol % and water: 0.1 mol %. Total oxygen removal was 99.53%.

Example 3, demonstrates the results when the product stream compositionis altered and Example 4 illustrates the effect when the oxygen removaltemperature and GHSV is varied.

In Example 3, the oxygen content at the oxygen removal reactor outlet is230 parts per million volume (“ppmv”), as compared to the oxygen contentat the inlet of the oxygen removal reactor which was 1,107 ppmv, areduction of 79.22%. The catalyst utilized was an Mn-based catalyst,MnOx. Oxygen removal reactor temperature was 150° C. Flow rate throughthe oxygen removal reactor was 9000 hr⁻. The other components of theproduct stream present at the oxygen removal reactor inlet are methane:62 ppmv, ethylene: 2.91 mol %, ethane: 96.10 mol %, propane: 47 ppmv,propylene: 2 ppmv, carbon monoxide (“CO”): 0.37 mol %, carbon dioxide(“CO₂”): 0.26 mol % and water (“H₂O”): 0.23 mol %. Other componentspresent at the oxygen removal reactor outlet are CO: 0.26 mol %, CO₂:0.17 mol % and water: 0.23 mol %. Total oxygen removal is calculated at79.22%. The components present at the oxygen removal reactor outlet arecooled to 40° C. and then fed to the inlet of an oxygen absorber unit 4containing BASF R3-16 as an absorbent 4 a. GHSV through the absorberunit was 3000 hr⁻¹. Absorber unit outlet composition is the following:O₂: 31 ppmv, CO: 0.25 mol %, CO₂: 0.16 mol %, and water: 0.23 mol %.Total oxygen removal is 97.20%.

Example 4 demonstrates the effect of using a different absorbent in theoxygen removal unit. The oxygen content at the oxygen removal reactoroutlet is 412 parts per million volume (“ppmv”), as compared to theoxygen content at the inlet of the oxygen removal reactor which was1,500 ppmv, a reduction of 72.53%. The catalyst utilized was an Mn-basedcatalyst, MnOx. Oxygen removal reactor temperature was 165° C. Flow ratethrough the oxygen removal reactor was 9000 hr⁻¹. The other componentsof the product stream present at the oxygen removal reactor inlet aremethane: 65 ppmv, ethylene: 3.76 mol %, ethane: 94.9 mol %, propane: 29ppmv, propylene: 29 ppmv, carbon monoxide (“CO”): 0.53 mol %, carbondioxide (“CO₂”): 0.40 mol % and water (“H₂O”): 0.2 mol %. Othercomponents present at the oxygen removal reactor outlet are CO: 0.38 mol%, CO₂: 0.53 mol % and water: 0.2 mol %. Total oxygen removal iscalculated at 72.53%. The components present at the oxygen removalreactor outlet are cooled to 40° C. and then fed to the inlet of anoxygen absorber unit 4 containing absorbent UOP 3A, commerciallyavailable from Honeywell Corporation as a series 3A molecular sieve.GHSV through the absorber unit was 3000 hr⁻¹. Absorber unit outletcomposition is the following: O₂: 53 ppmv, CO: 0.02 mol %, CO₂: 0.14 mol%, and water: 0.01 mol %. Total oxygen removal is 96.47%.

The various methods, systems, and techniques described above provide anumber of ways to carry out the application. Of course, it is to beunderstood that not necessarily all objectives or advantages describedcan be achieved in accordance with any particular embodiment describedherein. Thus, for example, those skilled in the art will recognize thatthe methods can be performed in a manner that achieves or optimizes oneadvantage or group of advantages as taught herein without necessarilyachieving other objectives or advantages as taught or suggested herein.A variety of alternatives are mentioned herein. It is to be understoodthat some embodiments specifically include one, another, or severalfeatures, while others specifically exclude one, another, or severalfeatures, while still others mitigate a particular feature by inclusionof one, another, or several advantageous features.

Furthermore, the skilled artisan will recognize the applicability ofvarious features from different embodiments. Similarly, the variouselements, features and steps discussed above, as well as other knownequivalents for each such element, feature or step, can be employed invarious combinations by one of ordinary skill in this art to performmethods in accordance with the principles described herein. Among thevarious elements, features, and steps some will be specifically includedand others specifically excluded in diverse embodiments.

Although the application has been disclosed in the context of certainembodiments and examples, it will be understood by those skilled in theart that the embodiments of the application extend beyond thespecifically disclosed embodiments to other alternative embodimentsand/or uses and modifications and equivalents thereof.

Various embodiments of this application are described herein, includingthe best mode known to the inventors for carrying out the application.Variations on those embodiments will become apparent to those ofordinary skill in the art upon reading the foregoing description. It iscontemplated that skilled artisans can employ such variations asappropriate, and the application can be practiced otherwise thanspecifically described herein. Accordingly, many embodiments of thisapplication include all modifications and equivalents of the subjectmatter recited in the claims appended hereto as permitted by applicablelaw. Moreover, any combination of the above-described elements in allpossible variations thereof is encompassed by the application unlessotherwise indicated herein or otherwise clearly contradicted by context.

All patents, patent applications, publications of patent applications,and other material, such as articles, books, specifications,publications, documents, things, and/or the like, referenced herein arehereby incorporated herein by this reference in their entirety for allpurposes, excepting any prosecution file history associated with same,any of same that is inconsistent with or in conflict with the presentdocument, or any of same that may have a limiting affect as to thebroadest scope of the claims now or later associated with the presentdocument. By way of example, should there be any inconsistency orconflict between the description, definition, and/or the use of a termassociated with any of the incorporated material and that associatedwith the present document, the description, definition, and/or the useof the term in the present document shall prevail.

It is to be understood that the embodiments of the application disclosedherein are illustrative of the principles of the embodiments of theapplication. Other modifications that can be employed can be within thescope of the application. Thus, by way of example, but not oflimitation, alternative configurations of the embodiments of theapplication can be utilized in accordance with the teachings herein.Accordingly, embodiments of the present application are not limited tothat precisely as shown and described.

Various embodiments of the invention are described above in the DetailedDescription. While these descriptions directly describe the aboveembodiments, it is understood that those skilled in the art may conceivemodifications and/or variations to the specific embodiments shown anddescribed herein. Any such modifications or variations that fall withinthe purview of this description are intended to be included therein aswell. Unless specifically noted, it is the intention of the inventorsthat the words and phrases in the specification and claims be given theordinary and accustomed meanings to those of ordinary skill in theapplicable art(s).

The foregoing description of various embodiments of the invention knownto the applicant at this time of filing the application has beenpresented and is intended for the purposes of illustration anddescription. The present description is not intended to be exhaustivenor limit the invention to the precise form disclosed and manymodifications and variations are possible in the light of the aboveteachings. The embodiments described serve to explain the principles ofthe invention and its practical application and to enable others skilledin the art to utilize the invention in various embodiments and withvarious modifications as are suited to the particular use contemplated.Therefore, it is intended that the invention not be limited to theparticular embodiments disclosed for carrying out the invention.

While particular embodiments of the present invention have been shownand described, it will be obvious to those skilled in the art that,based upon the teachings herein, changes and modifications may be madewithout departing from this invention and its broader aspects and,therefore, the appended claims are to encompass within their scope allsuch changes and modifications as are within the true spirit and scopeof this invention.

A glossary of elements in FIG. 1:

-   1. Heater-   2. Oxygen Removal Reactor-   2 a. Catalyst Bed-   3. Cooler-   4. Absorber Unit-   4 a. Absorbent or Molecular Sieve Bed-   6. ODH Product Stream-   7. Supply Line-   I1. Heater Inlet-   I2. Oxygen Removal Reactor Inlet-   I3. Cooler Inlet-   I4. Absorber Unit Inlet-   O1. Absorber Unit Outlet

A glossary of elements in FIG. 2:

-   1. Heater-   2. Oxygen Removal Reactor-   2 a. Catalyst Bed-   3. Cooler-   4. Absorber Unit-   4 a. Absorbent or Molecular Sieve Bed-   5. Heat Recovery Exchanger-   6. ODH Product Stream-   7. Supply Line-   I1. Heater Inlet-   I2. Oxygen Removal Reactor Inlet-   I3. Cooler Inlet-   I4. Absorber Unit Inlet-   O1. Absorber Unit Outlet

A glossary of elements in FIG. 3:

-   1. Heater-   2. Oxygen Removal Reactor-   2 a. Catalyst Bed-   3. Cooler-   6. ODH Product Stream-   7. Supply Line-   I1. Heater inlet-   I2. Oxygen Removal Reactor Inlet-   I3. Cooler Inlet-   O2. Cooler Outlet

What is claimed is:
 1. A method of removing oxygen from an oxygencontaining product stream of an oxidative dehydrogenation process,comprising: contacting the product stream of the oxidativedehydrogenation process with at least one oxygen removal catalyst in atleast one oxygen removal reactor at a first elevated temperature;wherein the product stream has a baseline oxygen content; and,recovering a first effluent stream from the at least one oxygen removalreactor, wherein the first effluent stream has a first oxygen content,wherein the first oxygen content of the first effluent stream is reducedas compared to the baseline oxygen content of the product stream;cooling the first effluent to a temperature in the range of 25° C. to50° C. before contacting the first effluent stream with at least oneoxygen absorbent in at least one oxygen absorber; and contacting thecooled first effluent stream with the at least one oxygen absorbent inthe at least one oxygen absorber unit in the absence of added unreacted(free) hydrogen at a second elevated temperature for a time sufficientto absorb oxygen from said first effluent stream, wherein said secondelevated temperature is lower than the first elevated temperature, andrecovering a second effluent stream, wherein the second effluent streamhas a second oxygen content which is reduced as compared to first oxygencontent of the first effluent stream; wherein the product streamcomprises at least two alkenes, at least two alkanes, carbon monoxide,carbon dioxide, water and oxygen; wherein the at least one oxygenremoval catalyst is a Mn-based oxygen removal catalyst; and wherein theat least one oxygen absorbent comprises at least one metal selected fromthe group consisting of Cu, Ag, Au, Zn, Cd, and Hg.
 2. The method ofclaim 1, wherein the contacting step with the Mn-based oxygen removalcatalyst is conducted at a first elevated temperature and for a timesufficient to remove at least 72.5% of the baseline oxygen content. 3.The method of claim 2, wherein the first elevated temperature is in atemperature range of from 150° C.-250° C.
 4. The method of claim 2,wherein the step of contacting the oxygen containing product streamcomprises contacting the product stream with the Mn-based oxygen removalcatalyst in the oxygen removal reactor is conducted at a GHSV rate inthe range of 4000-9000 hr¹.
 5. The method of claim 1, wherein the atleast one oxygen absorbent comprises a molecular sieve.
 6. The method ofclaim 1, wherein the contacting step with the Mn-based catalyst isconducted at a first elevated temperature and for a time sufficient toremove greater than 90% of the baseline oxygen content.
 7. The method ofclaim 1, wherein the total oxygen removed from the oxygen containingproduct stream of the oxidative dehydrogenation process is greater than96 wt. % after the absorbent step.
 8. The method of claim 1, wherein theMn-based catalyst comprises MnOx.
 9. The method of claim 1, wherein theMn-based catalyst comprises a mixed oxide of Mn and at least one othermetal.
 10. The method of claim 1, wherein the oxygen containing productstream from the oxidative dehydrogenation process comprises ethylene andpropylene, ethane and propane, carbon monoxide, carbon dioxide, waterand oxygen.
 11. The method of claim 10, wherein the oxygen containingproduct stream from the oxidative dehydrogenation process furthercomprises methane.
 12. The method of claim 1, wherein the recoveredsecond effluent stream comprises a reduced amount of carbon monoxide ascompared to the carbon monoxide content of the oxygen containing productstream from the oxidative dehydrogenation.
 13. The method of claim 1,wherein the recovered second effluent stream comprises a water contentin an amount in the range of less than or equal to the water content ofthe oxygen containing product stream from the oxidative dehydrogenation.14. The method of claim 1, wherein the recovered second effluent streamcomprises a carbon dioxide content in an amount in the range of lessthan, equal to, or more than the carbon dioxide content of the oxygencontaining product stream from the oxidative dehydrogenation.
 15. Themethod of claim 1, wherein the at least two alkanes comprise methane,ethane and propane.
 16. The method of claim 1, wherein the at least twoalkenes comprise ethylene and propylene.
 17. The method of claim 1,wherein the total oxygen removed from the oxygen containing productstream of the oxidative dehydrogenation process is greater than 99 wt. %after the absorbent step.
 18. The method of claim 2, wherein the step ofcontacting the oxygen containing product stream comprises contacting theproduct stream with the Mn-based oxygen removal catalyst in the oxygenremoval reactor is conducted at a GHSV rate in the range of 4180-9000hr¹.
 19. The method of claim 1, wherein the at least one oxygenabsorbent comprises at least one metal selected from Cu and Zn.